A window system called a multi-window system, in which plural windows can be displayed, is known. In a case where the multi-window system is used in an electronic device having a small display screen, such as a mobile phone, difficulty of an operation to select a desired window increases as a greater number of windows is displayed. For example, if a great number of windows is displayed on a screen at once, the size of each window has to be smaller, which makes it difficult to recognize a content of each window. Conversely, if each window is displayed in an appropriate size so that a user is able to recognize a content of each window, only some of the windows are displayed.
As a technique for improving operability in the multi-window system, techniques described in patent documents 1 and 2 are known. The techniques described in patent documents 1 and 2 are techniques by which a list display window is displayed in a display area and the list display window displays a list showing an arrangement of all windows, including any hidden windows.
Patent Document 1: JP-A-2003-280630
Patent Document 2: JP-A-2007-122633
However, if the above list display window is displayed in an electronic device having a small display screen, the list display window is overlapped on a currently displayed window. This reduces visibility of a content of the currently displayed window. Further, to avoid hiding the currently displayed window as much as possible, the size of the list display window has to be smaller. In this case, it becomes difficult to recognize a content of each window that is displayed in the list display window, which makes it difficult to recognize an arrangement of the windows.
An object of the present invention is to display a window group, in a case where plural windows can be displayed and a display area is small, so that a user is able to recognize an arrangement of windows included in the window group, and is able to recognize easily a content of at least a part of the window group.